Konjac has been eaten in the past because it has specific taste and palatability and is a low calorie food. Konjac is produced as follows: To konjac powder mainly consisting of glucomannan, water is added usually in the quantity by 20-50 times more (weight) than the powder, and the mixture is left for about 1 to 2 hours at the temperature of about 30.degree. C. for swelling. Then, the temperature is increased to about 65.degree. C., and alkaline solution such as lime or sodium carbonate is added. It is then mixed and is left for about 20 to 60 minutes to coagulate glucomannan.
Because alkaline substance (coagulant) remains in the coagulated product, the coagulated product normally exhibits strong alkalinity of about pH 12. To obtain better taste and palatability, attempts have been made to decrease the pH value of konjac and to coagulate glucomannan at lower alkalinity. An alkalinity of at least pH 10 is required to coagulate glucomannan within adequate time A new method has also been proposed, in which the coagulated konjac is heated to about 60.degree.-80.degree. C. and the excessive alkaline substances are neutralized by processing it with a solution of acidic substance for about 10 to 20 minutes. Once coagulated, glucomannan maintains its coagulated status even when neutralized.
However, in the neutralizing process of the coagulated product of glucomannan as described above, the acidic substances are not uniformly diffused in the entire coagulated product. The final product thus produced is not homogeneous in quality and the process is by no means satisfactory
Also, the neutralization of konjac causes the loss of elasticity, which is specific to konjac, and this decreases the taste and palatability of the food.
Further, when it is used simultaneously with other food materials, water is gradually released from the konjac, and the other food materials often become moist.